Due to the large scale of data that Internet search engines process, it can be difficult to summarize all of the search results for a particular user's query. One example where search engines can have difficulty is in estimating the number of search results for a query. This can be affected by multiple factors, such as conserving time spent counting the search results by only processing a portion of the search results or filtering the search results before they are counted. For example, duplicate or nearly duplicate search results can be filtered out. Duplicate search results can skew the estimation of the number of search results.
Summarizing search results can occur, for example, when the search engines employ “faceted search.” In the case of faceted search, the search engine presents to the user, alongside the search results, histograms summarizing the search results by different “facets.” For example, product search engines frequently show histograms of the results by price, by brand, or by type. A histogram can include several “buckets” and the histogram presents the number of results that fall into each bucket. For example, in a price histogram, the buckets can correspond to price ranges (e.g., Up to $100, $100-$200, and $200-$300). Each price is labeled by the number of products that match the user's query and whose price falls within that price range bucket.